where \(b_1^+(t_{b_1},b_1)\) , \(b_1^-(-t_{b_1}+\iota \frac{\beta }{2},b_1)\) , where \(\beta =2\pi /\kappa _H\)  and \(t_{b_1}\)  is the boundary time for the radiation region in black hole patch, correspond to the boundaries of radiation regions in right and left wedges of the black hole patch repectively and \(Q\)  is the central charge of 2D CFT. Central charge \(Q\)  take two numeric values, 1 for bosons and \(1/2\)  for fermions. Geodesic distance between the two points \(l_1\)  and \(l_2\)  for the 2D part of metric REF  is given by the following expression [1]}
\(d(l_1,l_2)=\sqrt{g_H(l_1)g_H(l_2)(U_H(l_2)-U_H(l_1))(V_H(l_1)-V_H(l_2))}\) 
